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प्रश्न
Name the following:
The photosensitive pigment present in the rod cells of the retina.
उत्तर
Rhodopsin
APPEARS IN
संबंधित प्रश्न
Name the defect of vision which can be corrected by a converging lens. Show clearly by a ray diagram how the lens corrects the defect.
Explain with the help of labelled ray-diagram, the defect of vision called hypermetropia, and hot it is corrected by a lens.
A person suffering from the eye-defect myopia (short-sightedness) can see clearly only up to a distance of 2 metres. What is the nature and power of lens required to rectify this defect?
To read a book held at a distance of 25 cm, will she need converging or diverging spectacle lenses?
A person cannot read newspaper placed nearer than 50 cm from his eyes. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length.
What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
State the main functions of the following:
Tears
When do we consider a student sitting in the class to be myopic? List two causes of this defect. Explain using a ray diagram how this defect of eye can be corrected.
Write whether the following is true or false:
A convex lens is used for correcting myopia.
Differentiate between:
Myopia and Hypermetropia.
Give Technical Term:
The type of lens used to correct myopia is
Nearsightedness: elongated eyeball : : farsightedness: _______
Nearsightedness : concave lens : : farsightedness : _______
Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.
Draw ray diagram showing myopic eye.
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
Complete the following table by observing the given figures:
| Figure → |  |
 |
| Points ↓ | ||
| (a) Name of the defect | ______ | ______ |
| (b) Position of the image | ______ | ______ |
| (c) Lens used to correct the defect | ______ | ______ |
Name the following:
Two kinds of accomodations.
Have a look at the posture of this girl who is reading a book and answer the questions which follow:
 |
- Name the problem she is facing.
- What are the two conditions shown in sections A and B of the eye as applicable to her.
- What kind of reading glasses does she need?
 |
 |
| A | B |
